Class: FiberConnectionPool

Inherits:
Object
  • Object
show all
Defined in:
lib/fiber_connection_pool.rb

Constant Summary collapse

VERSION = 
'0.2.4'
RESERVED_TTL_SECS =

reserved cleanup trigger

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SAVED_DATA_TTL_SECS =

saved_data cleanup trigger

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Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ FiberConnectionPool

Initializes the pool with ‘size’ instances running the given block to get each one. Ex:

pool = FiberConnectionPool.new(:size => 5) { MyConnection.new }

Raises:

  • (ArgumentError) 


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# File 'lib/fiber_connection_pool.rb', line 17

def initialize(opts)
  raise ArgumentError.new('size > 0 is mandatory') if opts[:size].to_i <= 0

  @saved_data = {} # placeholder for requested save data
  @reserved  = {}   # map of in-progress connections
  @treated_exceptions = [ PlaceholderException ]  # list of Exception classes that need further connection treatment
  @last_reserved_cleanup = Time.now # reserved cleanup trigger
  @available = []   # pool of free connections
  @pending   = []   # pending reservations (FIFO)
  @save_data_requests = {} # blocks to be yielded to save data
  @last_data_cleanup = Time.now # saved_data cleanup trigger

  @available = Array.new(opts[:size].to_i) { yield }
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &blk) ⇒ Object (private)

Allow the pool to behave as the underlying connection

Yield the connection within execute method and release once it is complete (assumption: fiber will yield while waiting for IO, allowing the reactor run other fibers)



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# File 'lib/fiber_connection_pool.rb', line 229

def method_missing(method, *args, &blk)
  execute(method) do |conn|
    conn.send(method, *args, &blk)
  end
end

Instance Attribute Details

#saved_data ⇒ Object

Returns the value of attribute saved_data.



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# File 'lib/fiber_connection_pool.rb', line 10

def saved_data
  @saved_data
end

#treated_exceptions ⇒ Object

Returns the value of attribute treated_exceptions.



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# File 'lib/fiber_connection_pool.rb', line 10

def treated_exceptions
  @treated_exceptions
end

Instance Method Details

#clear_save_data_requests ⇒ Object

Clear any save_data requests in the pool. No data will be saved after this, unless new requests are added with #save_data.



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# File 'lib/fiber_connection_pool.rb', line 81

def clear_save_data_requests
  @save_data_requests = {}
end

#gathered_data ⇒ Object

Return the gathered data for this fiber



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# File 'lib/fiber_connection_pool.rb', line 74

def gathered_data
  @saved_data[Fiber.current]
end

#has_connection?(conn) ⇒ Boolean

True if the given connection is anywhere inside the pool

Returns:

  • (Boolean) 


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# File 'lib/fiber_connection_pool.rb', line 110

def has_connection?(conn)
  (@available + @reserved.values).include?(conn)
end

#query(sql, *args) ⇒ Object

Avoid method_missing stack for ‘query’



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# File 'lib/fiber_connection_pool.rb', line 102

def query(sql, *args)
  execute('query') do |conn|
    conn.query sql, *args
  end
end

#recreate_connection(new_conn) ⇒ Object

DEPRECATED: use with_failed_connection



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# File 'lib/fiber_connection_pool.rb', line 115

def recreate_connection(new_conn)
  with_failed_connection { new_conn }
end

#release_data(fiber) ⇒ Object

Delete any saved_data for given fiber



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# File 'lib/fiber_connection_pool.rb', line 87

def release_data(fiber)
  @saved_data.delete(fiber)
end

#reserved_cleanup ⇒ Object

Delete any reserved held for dead fibers



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# File 'lib/fiber_connection_pool.rb', line 140

def reserved_cleanup
  @last_reserved_cleanup = Time.now
  @reserved.dup.each do |k,v|
    release(k) if not k.alive?
  end
end

#save_data(key, &block) ⇒ Object

Add a save_data request to the pool. The given block will be executed after each successful call to -any- method on the connection. The connection and the method name are passed to the block.

The returned value will be saved in pool.saved_data[key], and will be kept as long as the fiber stays alive.

Ex:

# (...right after pool's creation...)
pool.save_data(:hey_or_hoo) do |conn, method|
  return 'hey' if method == 'query'
  'hoo'
end

# (...from a reactor fiber...)
myfiber = Fiber.current
pool.query('select anything from anywhere')
puts pool.saved_data[myfiber][:hey_or_hoo]
  => 'hey'

# (...eventually fiber dies...)
puts pool.saved_data[myfiber].inspect
  => nil



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# File 'lib/fiber_connection_pool.rb', line 68

def save_data(key, &block)
  @save_data_requests[key] = block
end

#save_data_cleanup ⇒ Object

Delete any saved_data held for dead fibers



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# File 'lib/fiber_connection_pool.rb', line 93

def save_data_cleanup
  @saved_data.dup.each do |k,v|
    @saved_data.delete(k) if not k.alive?
  end
  @last_data_cleanup = Time.now
end

#save_data_for_fiber ⇒ Object

DEPRECATED: use save_data



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# File 'lib/fiber_connection_pool.rb', line 33

def save_data_for_fiber
  nil
end

#stop_saving_data_for_fiber ⇒ Object

DEPRECATED: use release_data



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# File 'lib/fiber_connection_pool.rb', line 38

def stop_saving_data_for_fiber
  @saved_data.delete Fiber.current
end

#with_failed_connection ⇒ Object

Identify the connection that just failed for current fiber. Pass it to the given block, which must return a valid instance of connection. After that, put the new connection into the pool in failed connection’s place. Raises NoReservedConnection if cannot find the failed connection instance.

Raises:



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# File 'lib/fiber_connection_pool.rb', line 124

def with_failed_connection
  bad_conn = @reserved[Fiber.current]
  raise NoReservedConnection.new if bad_conn.nil?
  new_conn = yield bad_conn
  @available.reject!{ |v| v == bad_conn }
  @reserved.reject!{ |k,v| v == bad_conn }
  @available.unshift new_conn
  # try to cleanup
  begin
    bad_conn.close
  rescue
  end
end